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41.
The optimum conditions for the removal of dissolved organic impurities from water using hydrogen peroxide (50%) followed by ultraviolet irradiation were investigated. The photochemically initiated hydroxyl radical (OH) oxidation reduced the total organic carbon (TOC) content of distilled water samples by about 88% and of tap water by 98%. Extraction with hexane of equal volumes of water samples before and after H2O2/u.v. treatment followed by gas chromatographic analysis of the concentrated extracts indicated that about 12% of the electron-capturing, residual organics remained after this treatment. These results support the conclusion drawn from total organic carbon analysis that this simple method yields water nearly free of organic impurities.  相似文献   
42.
Improvements in smoking cessation interventions for pregnant smokers are needed. One major step is to examine the potential effectiveness of nicotine replacement therapy (NRT). The potential benefits of providing pregnant women with NRT to help them quit smoking are still unknown; early interventions to test the effectiveness and efficacy are vital to advancing the field. This paper describes recruitment efforts for a multiclinic trial to test the effectiveness of NRT use in addition to behavioral therapy in promoting cessation during pregnancy. The biggest challenge is recruiting sufficient numbers of pregnant women. This paper discusses specific obstacles for recruitment and solutions. Knowing the potential pitfalls to recruiting pregnant women into these trials can lead to better studies and thus improved outcomes.  相似文献   
43.

Purpose

To investigate the effects of short-term orthokeratology (OK) on accommodation and binocular visual function in young adults.

Methods

Twenty-four myopes (18 to 38 years) were fitted with OK lenses in both eyes. Best corrected distance visual acuity (VA), subjective and objective refractions, corneal topography and a series of binocular vision tests were measured at baseline (BL) before lens wear and then repeated after 28 nights of OK. Data from 15 subjects who demonstrated successful OK lens fit are reported.

Results

Corneal flattening and hyperopic shifts in spherical equivalent refractive error (all p?<?0.001) after 28 nights of OK indicated myopic correction. Improvement in best corrected distance VA was measured after OK (right eye p?=?0.021; left eye p?=?0.014). Although there was no significant change in mean distance and near phorias and stereoacuity scores after OK compared to BL, there was a significant reduction in standard deviation (SD) and range of data (distance p?=?0.01; near p?=?0.02; stereoacuity p?<?0.001). While there appeared to be an improvement in distance accommodative facility after OK, this failed to reach statistical significance (p?=?0.053). Furthermore, there was no change in AC/A gradients with ±1 D and ±2 D lenses after OK compared to BL.

Conclusions

Binocular vision remained unchanged after OK, although variability of phoria and stereoacuity measures reduced. This suggests that OK improves or maintains accommodative and binocular vision function in young adult myopes who achieve good vision with OK. Myopes with phorias outside normal ranges and/or poor distance accommodative facility may benefit most with OK, in binocular and accommodative function.  相似文献   
44.
Trihalomethane (THM) concentrations in blood and tap water were measured for 50 women living in two locations with different bromide concentrations and disinfectant types. Blood samples were taken from each woman early in the morning prior to any major water-use activity and again immediately after showering. Each residence was sampled for THMs in tap water prior to the woman's shower. Cobb County, GA, tap water exhibited high THM concentrations composed primarily of chloroform. Corpus Christi, TX, tap water exhibited lower THM concentrations with significant proportions of brominated THMs. THMs in tap water and blood were compared using mole fraction speciation, extent of bromine incorporation, and correlation analysis. Results indicated that THMs in the blood rose significantly as a result of showering, that showering shifted the THM distribution in the blood toward that found in the corresponding tap water, and that THMs measured in the blood of women living in the two locations reflected species and concentration differences in their respective tap waters. In general, blood concentrations were not significantly correlated with tap water concentrations. This finding suggests that other factors, in addition to tap water concentrations, may be important in determining THM concentrations in the blood.  相似文献   
45.
One strategy to prevent obesity could consist in the inhibition of the pancreatic lipase (PL). In an attempt to find natural antiobesity agents, phenolic compounds (PCs) and plant extracts were investigated on PL activity. Epigallocatechin-3-gallate > kaempferol and quercetin were detected as potent PL inhibitors, with ICs50 of 0.8, 13.4 and 21.5 μM, respectively. Plant extracts from green tea and grape seed also shown potent inhibitory effect. Selected PCs were then assayed in an in vitro model of simulated intestinal fat digestion, based on the lipolysis of triolein. In such conditions closer to physiological reality, resveratrol, but also epigallocatechin-3-gallate and quercetin reduced the triolein digestion to ±50%. This could delay or decrease in vivo fatty acid absorption by enterocytes. This work therefore suggests that some PCs, at concentrations easily reached in the intestine following ingestion of tea beverages, fruits or vegetables, but also flavonoid-enriched supplements or functional food, are potential candidates for obesity prevention.  相似文献   
46.
47.
The design and production of Ti-6Al-4V ELI customized dental implants   总被引:1,自引:0,他引:1  
This paper addresses the production of customized Ti-6Al-4V ELI dental implants via electron beam melting (EBM). The melting of Ti-6Al-4V ELI powder produces implants with great biocompatibility, fi ne mechanical performance, and a high bone ingrowth potential. The EBM technology is used to produce one-component dental implants that mimic the exact shape of the patient’s tooth, replacing the traditional, three-component, “screw-like” standardized dental implants currently used. The new generation of implants provides the possibility of simplifying pre-insertion procedures leading to faster healing time, and the potential of better and stronger osseointegration, specifi cally through incorporating lattice structure design.  相似文献   
48.
To determine if the sexually dimorphic area (SDA) of the gerbil hypothalamus affects male sexual behavior through its projections to the retrorubral field (RRF) or ventrolateral periaqueductal gray (PAGvl), these pathways were lesioned asymmetrically. Unilateral radio frequency lesions of the lateral SDA (LSDA), the major source of the pathways, impaired mating when combined with contralateral RRF, but not PAGvl, lesions. N-methyl-{d}-aspartate (NMDA) lesions of the medial SDA, LSDA, and the area between them (the total pathway source) eliminated mating when combined with contralateral, but not ipsilateral, NMDA lesions of the RRF. To determine if A8 cells contributed to these effects, males received NMDA in the SDA and NMDA or 6-hydroxydopamine in the contralateral RRF. When combined with large SDA lesions, A8 lesions impaired but did not eliminate mating. Thus the SDA–RRF pathway, but not an SDA-A8 pathway, is essential for sexual behavior in male gerbils. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
49.
50.
Master-planned estates (MPEs) are becoming increasingly important as a part of the urban residential fabric and have recently begun to attract significant research attention. Our purpose in this article is to engage critically with understandings of MPEs in the Australian context and to suggest the need for both empirical and theoretical expansion. We draw on research into MPEs in the greater metropolitan region of Sydney and demonstrate how their diverse form and character exceed the parameters of Blakely and Snyder's (Fortress America, Brookings Institution Press, Washington, DC, 1997) influential and widely cited typology of MPEs. In a move towards grounded theory, we build from our findings to suggest three key analytical dimensions needed to equip us with more complex and theory-driven understandings of the dynamic forms and outcomes of MPE development: (i) the nature of governance mechanisms that produce MPEs and govern life within them; (ii) the influence of housing market context on the unfolding of urban social processes; and (iii) the dynamic and lived nature of neighbourhood and community. These dimensions are aimed to capture the empirical multiplicity of the MPE phenomenon and to broaden the scope of the theoretical and analytical frameworks that have characterised their Australian analysis. It is our hope that analysis framed by these expanded dimensions can contribute to the project of enhancing theoretical recognition of urban difference under distinct and unique Australian conditions.  相似文献   
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